Description
When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | — | 153.5.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | thunderbird | No fix yet | — |
| Debian 13 | thunderbird | 1:153.5.1esr-1~deb13u1 | — |
| Debian 12 | thunderbird | 1:153.5.1esr-1~deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | thunderbird | No fix yet | — |
| Ubuntu 26.04 LTS | thunderbird | No fix yet | — |
| Ubuntu 24.04 LTS | thunderbird | No fix yet | — |
| Ubuntu 22.04 LTS | thunderbird | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 153.5.1-1.1 | openSUSE-SU-2026:12224-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 153.5.1-1.amzn2.0.1 | ALAS2-2026-4057 |
Advisories 3
- WID-SEC-2026-4064 Mozilla Produkte (Thunderbird, Firefox ESR und Firefox): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALAS2-2026-4057 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 2, 2026
- openSUSE-SU-2026:12224-1 MozillaThunderbird-153.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Oct 23, 2026